Casting mold



May 14, 1935. F POE 2,001,583

CASTING MOLD Original Filed March 7, 1931 INVENTOR ATTORNEY Patented May14, 1935' CASTING MOLD Fred M. Poe, Suffern, N.- Y., assignor to TheAmerican Brake Shoe and Foundry Company, NewYork, .N. Y., a corporationof Delaware Originalapplication, March. 7', 1931, Serial No.

520,782. Divided and this application August 16,1933, Serial No. 685,333

' manent molds and which are intended for use in the manufactureofrailway brake shoes and other castings which are produced in largequantities; The pouring gate of a repetition mold tapers inwardly and itis the practice to leave this pouring gate partly filled with moltenmetal at the conclusion of the pouring operation, l'his molten metal inthe pouring gatecools and forms a tapered sprue which is connected withthecasting in the mold cavity. The cast brake shoe in cooling shrinkstoward its middle and when the'pouring gate is located at an end of themold cavity the sprue will anchor in the'pouring gate and will preventthe natural shrinkage of the shoe and cause the shoeto shrink toward thepouring gate end and set up stresses and strains in the mold which willcause the shoe to bind in an allmetalmojld and to damage any wall of amold cavity whichmay be made of refractory material.

The object of the invention is to relieve the anchorage of the sprue inthe pouring gate and to permit the natural shrinkage of the cast shoetoward its middle and to avoid damage to refractory walls of the moldcavity by providing the pouring gate with a frangible core which willbreak down under the pulling strains. of the shrinking shoe upon thesprue and permit the sprue to move inwardly into the mold cavity.

In the selected embodiment of my invention illustrated in theaccompanying drawing,

Fig. 1 is a longitudinal sectional view of my improved mold.

Fig. 2 is a side elevational view of the end portion of the mold whereinthe pouring gate is located. 1

Fig. 3 is a plan view of the end portion of the drag taken on theparting as indicated by the line 3-3 on Fig. 2, the pouring gate corebeing shown in section.

Fig. 4 is a plan view of an end portion of the cope taken on the partingand showing the pouring gate core in section.

In the accompanying drawing, a suitable base 5 is provided with a pairof upright brackets 5 having bearings 7 in which trunnions on the drag 8are journaled so that the mold may be pivoted in the bearings to beturned either into vertical position or into horizontal position. Thedrag comprises a metal shell 9 having a block 10 of refractory materialsecured in position therein by means of the ribs H and a suitablematerial .for the frangible core in the pouring gate this it, such .aslead, Babbitt metal or other soft metal, or carborundum, Portland cementor other plastic substance, in grooves E2 in said' ribs. Metal chillblocks hi and 15 are clamped against the opposite ends of the block isby adjusting 5 bolts l6 mounted in the end walls of the shellQ The copell comprises a metal shell l8 having a refractoryblock l9 secured inposition therein by ribs 29 having grooves 21 with a suitable ma terialM such as that used in the grooves i2.

The mold cavity is formed in the refractory blocks 'lllfand l9 and thechill blocks 14 and 15 with a passage P connectingwith one end of themold cavity. The end wallsof the shells 9 and i8 are cut away to receivethe neck 22 of the 15 sectional'pouring gate 23. The section 24 of thegate is secured to the shell 9 by nuts 25 on the bolts l5 and thesection 26 is secured to the shell l8 by bolts2l and nuts 28. Theparting of the mold extends along the opposing faces of the sections 24and 26 of the pouri gate and along opposing faces of the cope and drag.A core or liner 29 preferably unitary, is arranged in the pouring gateand the passage P and extends to the adjacent end of the mold cavity.This core conforms to the'inner walls of the pouring gate 23 and thepassage P and ithas a tapered opening therein to receive the moltenmetal. The core is frangible so that it may break down when the castingis cooling and shrinking to prevent damage to the refractory materialit] and l9, and it is also preferably porous to permit the escape ofgases during the pouring operation. The core may be made of sand like orsubstantially like sand cores customarily -made in foundry practice. Themolten metal is poured through the core of the pouring gate into themold cavity and more orless metal remains in the pouring gate accordingto custom. As the casting cools in the mold and the molten metal coolsin the pouring gate to form the sprue the shrinkage of the casting whichis normally toward the middle of the shoe and the shrinkage of the spruewill be opposed and if it were not shrinkage would produce stresses andstrains of the shoe on the walls of the mold cavity to such an extentthat the refractory walls are very likely to be damaged; and damage tothe refractory walls may make the mold unserviceable until the wallshave been replaced or repaired and comparatively slight damageordinarily involves considerable labor and time to repair. Butthefrangiblecore 29 crushes under the shrinking strains of the shoe andsprueand permits the shoe to shrink naturally and also permits the sprueto shrink naturally and move into 7 the mold cavity to compensate forthe shrinkage of the shoe to which it is integrally connected. The

mold selected for illustration is designed for casting a brake shoe inupright position (Fig. 1) and the refractory material It in the cope hasa centrally located recess 30 to receive the cores 3| and 32 and the lugstrap 33 for forming the attaching lug on the back of the shoe 'at themid- 1 die thereof. These lug cores andstraps are assembled as a unitwith the reenforce insert 34 which is arranged in the mold cavity forembedment in the cast shoe at the back thereof. This unit is held inplace in the mold by any suitable means such as the looped wire 35 and'aspacer 36 may be provided between the recess 30 and the shell 18 toprotect the refractory material against the crushing action which wouldoccur when too much tension is put upon the wire 35 by'the tensioningmeans 35 V the end cores 3! unless the shoe is to have end Brake shoesare customarily provided with end lugs on the back thereof and if thecavities for these lugs were formed in the refractory material the lugswould be liable to damage the refractory when the cast shoe shrinks incooling. Therefore I provide frangible cores 31in the refractory IQ ofthe cope, which cores are suitably shaped toform the end lugs on theback of the shoe and are frangible to crush under the shrinking strainsof the shoe. When a brake, shoe cast in the mold shown in Fig. 1 of thedrawing cools the casting 'will'shrink toward the middle and pull thesprue slightly into the mold cavity, thereby crushing the -frangibleliner 29. At the same time the cores 31. will be. crushed by the endlugs on the back of the shoe. It will not be necessary to providepouring gate breaks down under the pressure of the sprue in shrinkingand under the pulling strain of the shoe in shrinking and if cores 3!are provided they also will break down under the pressure of the endlugsof the shoe and the shrinkage of the shoe. The core 29, and: alsothe core 31 if used, can be readily replaced for each casting operation,but the blocks I0 and I9 which constitute the greater part of the wallsof the mold cavity will remain intact without becoming damaged byshrinkage of the shoe in cooling. After, the casting has cooledsufliciently the cope and drag may be separated, the casting removed andthe cope and drag prepared for a repetition casting, and theseoperations may be repeated as often and as frequently as required. Ihave illustrated the invention in a selected embodiment for casting abrake shoe, but I do not limit the invention to this particular use, norto the particular construction andarrangement of parts herein shown anddescribed, but I reserve .the right to make any changes andmodifications which may be necessary or desirable fprgtditferentcastings or for other purposes and within the scope of thefollowingclaim.

Iclaim: i a A repetition mold for casting brakeshoes and the like andhaving an elongated mold cavity, a

tapered pouring gate extendingthrough one end of the mold in thedirection of the length of the V mold cavity and communicating with theadjacent end of the mold cavity, a tapered frangible core in saidpouring gate, a wall of the mold cavity being made of refractorymaterial and having recesses thereinto form projections on the castingadjacent the ends thereof, and frangible cores in said recesses attheopposed ends, thereof, the core-in the pouring gate adapted to becrushed by the movement of the sprue as the sprue shrinks and'the coresin the recesses adapted to be crushed by the movement of the projectionstherein as the casting" shrinks towards of the cavity wall.

, its middle, and thereby permitting the castingto shrink in its normalway from itsends towards its middle without damage to the refractorypart FRED1M.PQE. 45..

